Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A non-contact sensor system is provided that comprises a first sensor
element and a rotary member disposed proximate the first sensor element
without physically contacting the first sensor element. The rotary member
may be configured to he rotated about an axis Y by a shaft configured to
pass through the rotary member along the axis Y at a value X. The non-con
act sensor system further comprises a second sensor element disposed on
the rotary member proximate the first sensor element without physically
contacting the first sensor element, and the first sensor element and the
second sensor element may be operatively coupled to facilitate sensing
the value X.

Claims:

1. A control unit for a non-contact sensor system, comprising: a signal
generator configured to produce a current in a first sensor element,
wherein the first sensor element is operatively coupled to a second
sensor element without physically contacting the second sensor element;
and a calculator configured to determine a value X in response to a
determination of a value Z associated with a rotary member disposed
proximate the first sensor element, wherein the rotary member is
configured to be rotated about an axis Y by a shaft configured to pass
through the rotary member along the axis Y at the value X, wherein the
value Z is associated with the rotation of the rotary member about the
axis Y,

2. The control unit of claim 17, wherein the value Z includes a
rotational distance of the second sensor element about the axis Y, and
wherein the value X includes a linear distance traveled by a wear pin
associated with a brake wear sensor.

Description:

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional application of U.S. patent
application Ser. No. 12/372,557, filed Feb. 17, 2009 and entitled,
"NON-CONTACT SENSOR SYSTEM AND METHOD FOR DISPLACEMENT DETERMINATION."
The '557 Application is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] This invention generally relates to non-contact sensor systems, and
more particularly, to inductive and capacitive non-contact sensor
systems.

BACKGROUND OF THE INVENTION

[0003] Various types of sensors are used throughout aircraft to provide
information about aircraft systems and operating conditions. Due in part
to the harsh operating conditions to which aircraft are subjected, the
sensors generally should be protected from these operating conditions.
Examples of such harsh operating conditions are high shock, high
vibration, high and low temperature extremes, humidity, wetness, dust,
snow, and ice. These harsh operating conditions are further exacerbated
by the high velocity at which aircraft travel. To account for these
operating conditions, aircraft sensors are generally robustly
constructed, often resulting in increased expense and weight. It is
therefore desirable to reduce the cost and weight of such sensors without
unacceptable loss in accuracy.

[0004] Additionally, many aircraft sensors have touching and/or moving
parts. Contacts in the sensors that require physical connections for
operation may wear out and become unreliable. Replacing these already
expensive sensors results in even greater expense.

[0005] In other industries, non-contact sensors have been employed in
response to some of the concerns associated with contact-based sensors.
Because of factors such as those noted above, these non-contact sensors
have not generally been used to replace contact-based sensors in
aircraft. Instead, some prior aircraft brake wear systems have generally
used visual inspection of a wear pin to determine the degree of brake
wear that has occurred. Several disadvantages to visual inspection exist,
including accuracy and timing of inspection. Thus, it is desirable to
improve the accuracy of measurement and the timing of inspection.

SUMMARY OF THE INVENTION

[0006] A non-contact sensor system comprises, in one embodiment, a first
sensor element and a rotary member disposed proximate the first sensor
element without physically contacting the first sensor element. The
rotary member may be configured to be rotated about an axis Y by a shaft
configured to pass through the rotary member along the axis Y at a value
X. The non-contact sensor system may further comprise a second sensor
element disposed on the rotary member proximate the first sensor element
without physically contacting the first sensor element, and the first
sensor element and the second sensor element may be operatively coupled
to facilitate sensing the value X.

[0007] In some embodiments, a control unit for an aircraft non-contact
sensor system comprises a signal generator configured to produce a
current in a first sensor element. The first sensor element may be
operatively coupled to a second sensor element without physically
contacting the second sensor element. In an embodiment, the control unit
further comprises a calculator configured to determine a value X in
response to a determination of a value Z associated with a rotary member
disposed proximate the first sensor element. The rotary member is
configured to be rotated about an axis Y by a shaft configured to pass
through the rotary member along the axis Y at the value X, and the value
Z is associated with the rotation of the rotary member about the axis Y.

[0008] Further, according to various embodiments, a computer readable
medium may have stored thereon a plurality of instructions comprising
instructions to generate a signal that causes a first current to flow in
an electrical circuit in a first non-contact sensor element. A first
electromagnetic field is generated in response to the signal, and the
first non-contact sensor element is disposed proximate a second
non-contact sensor element without physically contacting the second
non-contact sensor element. The instructions may further comprise
instructions to sense a second electromagnetic field by a sensing circuit
in the first non-contact sensor element, the second electromagnetic field
being generated in response to a second current flowing through a
resonant circuit on the second non-contact sensor element. The second
current is generated in response to the first electromagnetic field and
the second non-contact sensor element is disposed on a rotary member that
is configured to be rotated about an axis Y by a shaft configured to pass
through the rotary member along the axis Y at a value X. The instructions
may further comprise instructions to determine the value X in response to
sensing the second electromagnetic field and in response to a value Z
associated with the rotation of the rotary member about the axis Y.

[0009] Additionally, various embodiments provide a non-contact sensor
system that comprises a first sensor element disposed within a first
member having an axis Y, and a second member configured to rotate about
the axis Y at a value X, wherein the second member is configured to
interface with the first member. The non-contact sensor system may
further comprise a second sensor element disposed on the second member
proximate the first sensor element, without physically contacting the
first sensor element, and the first sensor element and the second sensor
element may be operatively coupled to facilitate sensing the value X.

[0010] Furthermore, various embodiments may provide a non-contact sensor
system that comprises a first sensor element disposed on an outside
surface of a chamber having an inside surface that is configured to
receive a piston, the piston being configured to move a value X within
the chamber, without physically contacting the first sensor element. The
noncontact sensor system may further comprise a second sensor element
disposed on the piston and separated by a wall of the chamber, and the
first sensor element and the second sensor element being operatively
coupled to facilitate sensing the value X.

[0011] Moreover, in accordance with various embodiments, a non-contact
sensor system may comprise a first sensor element disposed on a
stationary member, and a second sensor element disposed on a rotational
member. The second sensor element is proximate the first sensor element,
without physically contacting the first sensor element, and the
rotational member is configured to facilitate selection of at least a
first position and a second position. In such embodiments, the first
sensor element and the second sensor element are operatively coupled to
facilitate sensing of the selected position.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0012] FIG. 1 illustrates a perspective view of a noncontact sensor system
for measuring brake wear according to an embodiment;

[0013] FIG. 2 illustrates a perspective view of a second noncontact sensor
system for measuring brake wear according to an embodiment;

[0014] FIG. 3 illustrates a cross-sectional view of a rotational member
for use in a non-contact sensor system according to an embodiment;

[0015] FIG. 4 illustrates a cross-sectional view of a non-contact sensor
system for measuring wheel rotation according to an embodiment;

[0016] FIG. 5 illustrates a cross-sectional view of a second noncontact
sensor system for measuring wheel rotation according to an embodiment;

[0017] FIG. 6 illustrates a cross-sectional view of a non-contact sensor
system for use with a pedal sensor according to various embodiments;

[0018] FIG. 7 illustrates a perspective view of a non-contact sensor
system for use with an autobrake switch according to an embodiment; and

[0019] FIG. 8 illustrates a cross-sectional view of a non-contact sensor
system for use with a hydraulic accumulator according to an embodiment.

DETAILED DESCRIPTION

[0020] The detailed description of various embodiments herein makes
reference to the accompanying drawing figures, which show various
embodiments and implementations thereof by way of illustration and its
best mode, and not of limitation. While these embodiments are described
in sufficient detail to enable those skilled in the art to practice the
embodiments, it should be understood that other embodiments may be
realized and that logical, electrical, and mechanical changes may be made
without departing from the spirit and scope of the invention. For
example, the steps recited in any of the method or process descriptions
may be executed in any order and are not necessarily limited to the order
presented. Moreover, many of the functions or steps may be outsourced to
or performed by one or more third parties. Furthermore, any reference to
singular includes plural embodiments, and any reference to more than one
component or step may include a singular embodiment or step. Also, any
reference to attached, fixed, connected or the like may include
permanent, removable, temporary, partial, full and/or any other possible
attachment option. Additionally, any reference to without contact (or
similar phrases) may also include reduced contact or minimal contact.

[0021] Various embodiments provide a non-contact sensor system that
comprises a first sensor element operatively coupled to a second sensor
element without physically contacting the second sensor element. For
example, the non-contact sensor system may use electromagnetism,
magnetism, induction, and/or capacitance to create and/or modify an
electromagnetic field between the first sensor element and the second
sensor element in order to cause current to flow in the first sensor
element and/or the second sensor element, without any physical
connections between the first sensor element and the second sensor
element. In various embodiments, any method of causing current to flow in
the second sensor element in response to a current flowing in the first
sensor element where the first sensor element does not physically contact
the second sensor element is contemplated and within the scope of the
present disclosure. Similarly, any sensor system configured to calculate
position information based on a relative location of a first sensor
element to a second sensor element, where the first and second sensor
elements are not in physical contact with each other, is contemplated
within the scope of the present disclosure.

[0022] The first sensor element, in various embodiments, comprises an
electrical circuit that may be disposed, for example, on a printed
circuit board that includes at least one electrically conductive track,
coil, circuit element or the like. Further the electrical circuit may
comprise standard electronic components not embodied on a printed circuit
board and/or the electrical circuit may comprise an integrated circuit.
The electrical circuit may comprise a plurality of circuits, such as an
excitation circuit, a sensing circuit, or the like. At least a portion of
the electrical circuit, for example, an excitation circuit, is configured
to carry an excitation signal that in turn generates a first
electromagnetic field. It should be noted that in various embodiments,
the electrical circuit and/or portions thereof may be located in one
place in the sensor system, or they may be located in separate places.
For example, the excitation circuit may be located in one location, and
the sensing circuit may be located in a separate location. The first
electromagnetic field generated by the electrical circuit of the first
sensor element is configured to induce a resonant current in a resonant
circuit disposed on the second sensor element. The resonant current
induced in the resonant circuit is configured to generate a second
electromagnetic field, and the second electromagnetic field is configured
to induce a sensing current in a sensing circuit that is part of the
electrical circuit on the first sensor element. The electromagnetic
coupling between the first sensor element and the second sensor element
is configured to vary with the relative position of the second sensor
element to the first sensor element, and the sensing current may thus be
used to determine the relative position of the second sensor element to
the first sensor element.

[0023] As noted above with respect to the first sensor element, in
accordance with various embodiments, it should be understood that the
first sensor element and the second sensor element may individually
comprise a plurality of sensor elements. For example, the first sensor
element may comprise two or more sensor elements, and/or the second
sensor element may comprise two or more sensor elements. These sensor
elements may be mounted respectively on a fixed member and a moveable
member. In various embodiments, the fixed member and the moveable member
may comprise active portions, for example, where the sensor elements are
located, and they may comprise inactive portions, for example, where the
sensor elements are not located. Various embodiments further comprise
sensor systems where the fixed member and the moveable member may
comprise only active portions, such that the fixed member is the first
sensor element and the movable member is the second sensor element. Thus
it should be understood that while various embodiments may be described
with a sensor element being disposed on a fixed and/or movable member, in
various embodiments the fixed and/or movable member may not be present,
or the first sensor element and/or second sensor element may be present
in the sensor system without being disposed on a fixed member and/or a
movable member. Further, it should be understood that while various
embodiments may he disclosed as comprising single sensor elements, these
sensor elements may comprise multiple sensor elements without departing
from the scope of the invention. It should further be understood that any
electrical circuit, now known or hereafter developed, that is capable of
providing the functionality disclosed herein is contemplated within the
scope of this disclosure.

[0024] According to various embodiments, a control unit may be used to
generate the excitation signal. The control unit may further be
configured to receive the sensing signal and perform signal conditioning
operations to determine the relative position of the second sensor
element to the first sensor element. As will be discussed further below,
the control unit may also be configured to determine a value associated
with an aircraft system in response to the relative position of the
second sensor element to the first sensor element. A separate control
unit may be used for each combination of the first sensor element and the
second sensor element, or a single control unit may be used to determine
a plurality of values associated with a plurality of aircraft systems in
conjunction with a plurality of first and second sensor element
combinations.

[0025] An aircraft brake wear measurement system, according to an
embodiment, is configured to determine how much an aircraft brake has
worn. The break wear is determined by measuring the displacement between
the brake's pressure plate (which includes the brake wear sensor's
reference point) and a piston housing. A wear pin is attached to the
pressure plate and passes through a rotational member that comprises a
second non-contact sensor element. The wear pin's geometry is configured
to rotate the rotational member as the wear pin moves linearly with the
pressure plate. The rotation of the rotational member is proportional to
the linear movement of the brake's pressure plate.

[0026] With reference to FIGS. 1 and 2, a brake wear non-contact sensor
system 10 according to an embodiment is configured to determine a
distance traveled by a wear pin 12 Wear pin 12 is attached to a brake
system pressure plate 11 that is configured to exert a controllable
braking force on a brake stack. As the brake stack wears, the distance
between pressure plate 11 and brake housing 13 increases.

[0028] As the brake stack begins to wear, pressure plate 11 moves further
from brake housing 13, and wear pin 12 is configured to cause rotational
member 15 to rotate a rotational distance Z about an axis Y along which
wear pin 12 is oriented. With momentary reference to FIG. 3, and
according to various embodiments, wear pin 12 may comprise a helix 19,
groove, flute, channel or the like that is configured to interface with a
key 9 in rotational member 15. Such an interaction may be configured to
convert the linear movement of wear pin 12 into a rotational movement of
rotational member 15 about the axis Y. As rotational member 15 rotates,
the relative position of rotational sensor element 16 to fixed sensor
element 17 changes.

[0029] In accordance with an embodiment where fixed sensor element 17
comprises a printed circuit board, the control unit causes an excitation
signal to flow through an excitation circuit, such as an excitation coil
(e.g., an antenna included in a printed circuit board) in fixed sensor
element 17. The excitation signal then causes a first electromagnetic
field to form in response to the excitation signal flowing through the
excitation coil. This first electromagnetic field is configured to be at
a resonant frequency of rotational sensor element 16, and induces a
current in rotational sensor element 16. This induced current in
rotational sensor element 16 is configured to generate a second
electromagnetic field, and the second electromagnetic field in turn is
configured to induce a current in a sensing circuit, such as a sensing
coil in fixed sensor element 17. This current is sensed by the control
unit via connector 18, and the current is used to determine the relative
position of fixed sensor element 17 to rotational sensor element 16. The
relative position is then used to determine the rotational distance Z
traveled by rotational sensor element 16 on rotational member 15. The
amount of rotation is proportional to a linear distance X traveled by
wear pin 12, and the control unit therefore is configured to determine
the linear distance X traveled by wear pin 12 and the brake wear
associated with linear distance X.

[0030] In accordance with various embodiments, rotational sensor element
16 may be located on one or more portions of rotational member 15. For
example, rotational sensor element 16 may comprise a plurality of sensor
elements disposed about the circumference of rotational member 15.
Rotational sensor element 16 may further be disposed continuously about
the circumference of rotational member 15. Further, various embodiments
may provide that rotational sensor element 16 is configured to rotate
about the axis Y without being disposed on rotational member 15, or
rotational member 15 and rotational sensor element 16 may be configured
to be the same component.

[0031] With reference to FIGS. 4 and 5, a non-contact wheel speed sensor
system 20 according to an embodiment comprises a fixed sensor element 27
disposed within a wheel axle 21 configured to interface with a wheel hub
23. Wheel hub 23 is configured to rotate about an axis Y, and wheel axle
21 is configured to be aligned with the axis Y.

[0032] As illustrated in FIG. 4, a fixed sensor element 27 comprises a
disk-shaped electrical circuit, for example, a disk-shaped electrical
circuit board configured to be disposed across wheel axle 21, such that a
vector normal to fixed sensor element 27 at any point is substantially
parallel to axis 29 of wheel hub 23. In various configurations, wheel hub
23 comprises a rotational sensor element 26 has a normal vector
substantially parallel to axis 29. Thus, in response to wheel hub 23
being engaged with axle 21, the sensing surfaces of fixed sensor element
27 and rotational sensor element 26 are substantially parallel to each
other.

[0033] As illustrated in FIG. 5, fixed sensor element 27 comprises an
electrical circuit, for example, a flexible flat circuit board disposed
circumferentially against a wall of wheel axle 21 and about axis 29 of
wheel hub 23. In such a configuration, wheel hub 23 comprises a
rotational sensor element 26 that is disposed circumferentially against a
wall of wheel hub 23 and about axis 29. Thus, in response to wheel hub 23
being engaged with wheel axle 21, the sensing surfaces of fixed sensor
element 27 and rotational sensor element 26 are substantially equidistant
from each other over the sensing surfaces. It should be understood that
fixed sensor element 27 may comprise a plurality of fixed sensor elements
disposed within wheel axle 21, and/or that rotational sensor element 26
may comprise a plurality of rotational sensor elements disposed on wheel
huh 23.

[0034] With reference to both FIGS, 4 and 5, in various embodiments, the
control unit is configured to cause an excitation signal to flow through
an excitation circuit such as an excitation cod in fixed sensor element
27. The excitation signal may then be configured to cause a first
electromagnetic field to form in response to the excitation signal
flowing through the excitation coil. This first electromagnetic field is
configured to be at a resonant frequency of rotational sensor element 26,
and is configured to induce a current in rotational sensor element 26.
This induced current in rotational sensor element 26 generates a second
electromagnetic field, and the second electromagnetic field in turn
induces a current in a sensing circuit, as a sensing coil in fixed sensor
element 27.

[0035] This current may then be sensed by the control unit via connector
28, and the current may be used to determine the relative position of
fixed sensor element 27 to rotational sensor element 26 in order to
determine a value X associated with the relative position about the axis
Y. The relative position may thus used to determine the amount of
rotation of wheel hub 23. Repeated position measurements may be used to
determine a velocity and/or acceleration of wheel hub 23 about axis 29.

[0036] According to various embodiments, and with reference to FIG. 6, a
non-contact pedal sensor is configured to determine the position of a
pedal, for example, as used in an aircraft. FIG. 6 illustrates two
non-contact pedal sensors 30, 40. It should be understood that in various
embodiments, both non-contact pedal sensors 30, 40 may be present, or
only one of non-contact pedal sensor 30 or non-contact pedal sensor 40
may be present. Both non-contact pedal sensors 30, 40 are illustrated in
FIG. 6 for purposes of illustration and description of an embodiment.

[0037] In such embodiments, as the pedal moves, a piston assembly 41 is
configured to move a distance X within a chamber 31, and a spring 32 is
configured to maintain piston assembly 41 in a starting position if a
force is not exerted on piston assembly 41. The relative position of
piston assembly 41 within chamber 31 is used to determine a position of
the aircraft pedal.

[0038] With continued reference to FIG. 6, in various embodiments, piston
assembly 41 comprises a first sensor element, such as magnet 36 disposed
on a piston head 35. On the outside of chamber 31, a fixed sensor element
37 is disposed over a distance sufficient to cover the total travel
distance of piston head 35. Chamber 31 separates magnet 36 and fixed
sensor element 37. Magnet 36 is configured to produce a electromagnetic
field, and as piston assembly 41 moves, the electromagnetic field induces
a current in a sensing circuit such as a sensing coil in fixed sensor
element 46. The current induced may thus be used by the control unit, via
transmission by connector 38, to determine a distance X traveled by
piston head 35 and thus a relative position of piston head 35 to fixed
sensor element 37 in order to determine the position of the aircraft
pedal. It should be understood that while a magnet is disclosed, various
embodiments of the invention comprise a second sensor element instead of
a magnet, where the second sensor element is configured to be an active
sensor element, such as a resonant circuit disclosed in other
embodiments, and may be operatively coupled to the first sensor element
via induction, capacitance, or the like.

[0039] In various embodiments, and with continued reference to FIG. 6,
piston assembly 41 may comprise a piston shaft 42 that is configured to
rotate a rotational member 47 about an axis Y in a manner similar to the
rotation of rotational member 15 by wear pin 12 (discussed above). A
fixed sensor element 46 is positioned on a fixed member 45 that is
substantially parallel to rotational member 47. A rotational sensor
element 48 is disposed on rotational member 47 without physically
contacting fixed member 45 or fixed sensor element 46. As noted above, in
various embodiments, fixed sensor element 46 may be disposed on only a
portion of fixed member 45, fixed sensor element 46 may be configured to
operate without fixed member 45, or fixed sensor element 46 may not be
disposed on fixed member 45. Further, in various embodiments, rotational
sensor element 48 may be disposed on only a portion of rotational member
47, or rotational sensor element 48 may be configured to operate without
rotational member 47 (e.g., where rotational sensor element 48 is present
in the sensor system without rotational member 47). According to various
embodiments, the sensor system may comprise fixed sensor element 46
and/or rotational sensor element 48 without comprising fixed member 45
and/or rotational member 47.

[0040] The control unit, in accordance with various embodiments, is
configured to cause an excitation signal to flow through an excitation
circuit such as an excitation coil in fixed sensor element 46. The
excitation signal causes a first electromagnetic field to form in
response to the excitation signal flowing through the excitation coil.
This first electromagnetic field is configured to be at a resonant
frequency of rotational sensor element 48, and induces a current in
rotational sensor element 48. This induced current in rotational sensor
element 48 generates a second electromagnetic field, and the second
electromagnetic field in turn induces a current in a sensing circuit
(e.g., a sensing coil) in fixed sensor element 46.

[0041] This current is sensed by the control unit via connector 48, and is
used to determine the relative position of fixed sensor element 46 to
rotational sensor element 48. This relative position is used to determine
the amount of rotation of rotational member 47. The amount of rotation is
proportional to a linear distance X traveled by piston assembly 41, and
the control unit therefore determines the linear distance X traveled by
piston assembly 41 and the pedal position associated with that linear
distance.

[0042] With reference now to FIG. 7, an autobrake switch sensor 50
according to an embodiment is disclosed. Autobrake switch sensor 50 is
configured to determine a position of knob 51, and knob 51 is configured
to select a plurality of options. Knob 51 is configured to turn the
autobrake off, and it is configured to select "LO," "MED," "HI," "MAX,"
or "RTO" options in connection with the autobrake.

[0043] It should be understood that in various embodiments, any number of
selections may be made by a selection sensor. For example, knob 51 may be
configured to select between two options, such as "ON" and "OFF." Knob 51
may further be configured to select between ten, or twenty, or more
options. In accordance with various embodiments, a sensor may be
configured to utilize a reconfigurable switch plate display 63, such that
the sensor may be configured to sense two options with one switch plate
display, and the sensor may be configured to sense more than two options
in another switch plate display.

[0044] To facilitate sensing the selection, according to various
embodiments, autobrake switch sensor 50 comprises a fixed sensor element
57 disposed proximate a rotational member 56 without physically
contacting rotational member 56. Rotational member 56 comprises a
rotational sensor element 59 that does not physically contact fixed
sensor element 57. Rotational member 56 is configured to be connected to
knob 51 with switch plate display 63 located between knob 51 and
rotational member 56, such that when knob 51 rotates, rotational member
56 rotates, but switch plate display 63 remains stationary.

[0045] In an embodiment, autobrake switch sensor 50 is configured to sense
a relative position of rotational sensor element 59 to fixed sensor
element 57 and thereby determine the selection indicated by the position
of knob 51 and rotational member 56. The control unit is configured to
cause an excitation signal to flow through an excitation circuit such as
an excitation coil in fixed sensor element 57. The excitation signal
causes a first electromagnetic field to form in response to the
excitation signal flowing through the excitation coil. This first
electromagnetic field is configured to be at a resonant frequency of
rotational sensor element 59 and to induce a current in rotational sensor
element 59. This induced current in rotational sensor element 59
generates a second electromagnetic field, and the second electromagnetic
field in turn induces a current in a sensing circuit (e.g., a sensing
coil) in fixed sensor element 57. This current is sensed by the control
unit via connector 58, and the current is used to determine the relative
position of fixed sensor element 57 to rotational sensor element 59. The
relative position is then used to determine the selection indicated by
knob 51 and rotational member 56. It should be noted that in various
embodiments, fixed sensor element 57 may be disposed on at least a
portion of a fixed member. Further, according to various embodiments,
rotational sensor element 59 may comprise a plurality of rotational
sensor elements disposed on rotational member 56, or rotational sensor
element 59 may function without rotational member 56, where rotational
member 56 is not included as part of the sensor system.

[0046] In accordance with various embodiments, knob 51 may be configured
to actuate fixed sensor element 57, rotational sensor element 59, and/or
the control unit. For example, knob 51 may be rotated to a desired
position, and then knob 51 may be pressed, pulled, and/or otherwise
actuated to facilitate activating the sensor system. In response to knob
51 being pressed and/or pulled, for example, a current may be configured
to flow through the excitation circuit in fixed sensor element 57.

[0047] In various embodiments, and with reference to FIG. 8, a hydraulic
accumulator volume sensor system 60 is configured to determine an amount
of available hydraulic fluid in hydraulic accumulator 61. A piston 62 is
disposed in hydraulic accumulator 61, and is configured to separate a
first section 64 from a second section 65. In an embodiment, first
section 64 is configured to be filled with nitrogen, and second section
65 is configured to be filled with hydraulic fluid. As hydraulic fluid is
utilized in an aircraft, the amount (e.g., a volume, weight, pressure,
etc.) of hydraulic fluid available in hydraulic accumulator 61 is
reduced, and piston 62 may move a distance X within accumulator 61.
Determining the position of piston 62 within hydraulic accumulator 61
facilitates determination of the amount of hydraulic fluid available. In
various embodiments, hydraulic volume sensor system 60 may be configured
to be used within pressure-bearing vessels to facilitate sensing a volume
within the pressure-bearing vessels.

[0048] Hydraulic accumulator volume sensor system 60 comprises a magnet 66
disposed on piston 62 proximate a wall of hydraulic accumulator 61. As
noted previously, although a magnet is disclosed, it should be understood
that various non-contact sensors described herein may be employed in
addition to and/or instead of magnet 66. Hydraulic accumulator volume
sensor system 60 further comprises a fixed sensor element 67 disposed
outside of hydraulic accumulator 61 over a distance sufficient to cover
the total travel distance of piston 62. Hydraulic accumulator 61
physically separates magnet 66 and fixed sensor element 67. Magnet 66 is
configured to produce a electromagnetic field, and as piston 62 moves,
the electromagnetic field is configured to induce a current in a sensing
circuit (e.g., sensing coil) in fixed sensor element 67. The current
induced is used by the control unit, via transmission by connector 68, to
determine a relative position of piston 62 to fixed sensor element 67 and
thereby facilitate determination of the available hydraulic fluid within
hydraulic accumulator 61.

[0049] In various embodiments, the control unit may comprise a processor
configured to control the various operations disclosed herein. Such
processors are known in the art, and any processor now known or hereafter
developed may be used to facilitate control of the control unit.
Additionally, the control unit may further comprise a computer readable
medium configured to provide instructions to the processor for carrying
out the various operations disclosed herein. The computer readable medium
may be embodied in any form readable by the processor that is now known
or hereafter developed. Examples of such computer readable media are
flash memory, solid state memory, magnetic discs (e.g., hard disks,
floppy discs, and the like), and optical discs (e.g., compact discs,
digital versatile discs, Blu-Ray discs, and the like).

[0050] The control unit, electronic circuits, integrated circuits, and the
like disclosed herein, and in accordance with various embodiments, may
comprise any electronic circuit configured to control the various
operations disclosed herein. The electronic circuit may comprise any
known electronic components (for example, transistors, capacitors,
diodes, resistors, and the like) configured to perform the various
calculations and/or determinations to determine position, displacement,
velocity, acceleration, and the like, relating to the sensor elements and
sensor systems disclosed herein. Such calculations may be performed
and/or carried out with or without a general-purpose processor, software,
or a computer readable medium. Such calculations may be preformed and/or
carried out with or without the use of an integrated circuit. It should
be understood that any method for determining the various
characteristics, outputs, readings, measurements, and the like,
associated with the sensor elements and sensor systems disclosed herein,
whether now known or hereafter developed, is contemplated within the
scope of the present disclosure. For example, the various circuits
disclosed herein may be configured to provide analog and/or digital
signals (e.g., digital pulse output from the fixed sensor element to the
control unit) for processing by the control unit.

[0051] Although various embodiments for a non-contact sensor system have
been disclosed, it should be understood that the present disclosure is
not limited to such applications. Various modifications will be apparent
to one skilled in the art in order to adapt the non contact sensor system
disclosed herein to other applications, and such other applications are
thus contemplated within the scope of the present disclosure.

[0052] In various embodiments, it may be desirable to determine a value X,
such as a linear position of an object. For example, a shaft may be
attached to the object, and as the object moves, the shaft causes a
rotational member to rotate about an axis Y. One non-contact sensor
element as disclosed herein may be attached to the rotational member, and
another non-contact sensor element may he located proximate to the first
non-contact sensor element without physically contacting the first
non-contact sensor element. In various embodiments, the rotational sensor
element and/or the fixed sensor element may be configured to function
without the rotational member and/or the fixed member. Using the
electromagnetism, capacitance, and/or induction principles discussed
herein, a linear position of the object may be determined by determining
the amount of rotation of the rotational member and a corresponding
rotational distance Z traveled by the second non-contact sensor element.
In some circumstances, it may also be desirable to determine the degree
of rotation of the rotational member, or other rotating object, apart
from a linear position of the object mentioned above.

[0053] Linear position of an object according to various embodiments may
also be determined by affixing a magnet to a portion of the object or an
element associated with the object. A non-contact sensor disclosed herein
may then be positioned proximate the magnet without physically contacting
the magnet. As the magnet moves with the object movement, the principles
disclosed herein associated with the non-contact sensor element may be
used to determine the relative position of the magnet to the non-contact
sensor element, and thus be used to determine the linear position of the
object.

[0054] In accordance with various embodiments, only one linear or
rotational position is determined, though it should be understood that
any number of calculations and/or values relating to the position
determination may be determined in accordance with physical principles.
For example, repeated linear position measurements may be used to
determine linear velocity and/or linear acceleration of an object.
Repeated rotational position measurements may be used to determine
rotational velocity and/or rotational acceleration of an object. A
volume, weight, mass, pressure, or the like determination may also be
made where a linear position measurement indicates the position of a
piston within a cylinder or other body. One skilled in the art will
appreciate that any number of calculations and/or determinations may be
made in accordance with principles disclosed herein.